Numbers, please! 3.75 megabytes of memory - The world's first hard disk
The IBM 350, the world's first hard disk, was released in 1956. As the RAMAC computer's memory, it had space for 3.75 megabytes of data.
Our article on the first hard disk with the storage space of less than three HD disks brought back memories of days gone by for many readers, such as when the first computer received its hard disk upgrade. We have therefore decided to update the article and republish it as “Numbers, please! classic”. Have fun!
The cradle of the magnetic hard disk lies in the laboratories of International Business Machines (IBM). The IBM 350 was the size of a closet and weighed almost a ton, including the cooling system. And the 50 magnetic disks in it were only able to store the equivalent of 3.75 megabytes.
The development of the IBM 305 RAMAC (Random Access Method Of Accounting And Control) began in 1952 in the Storage Development Laboratory newly founded by the computer group. The aim was to enable fast real-time data processing via a computer, which was more effective than the previous cumbersome and error-prone processing via punched cards. In addition, more and more data had to be processed and the Hollerith punch cards were reaching their limits and taking up more and more storage space.
(Image:Â IBM Archives)
Disks as the most effective memory
Various types of storage media were tested: from magnetic tapes to magnetic drums and magnetic disks. In the end, magnetic tapes were not used because it took far too long to rewind from one position to another. Magnetic, rotating drums, on the other hand, took up too much space, offered too little memory and were therefore ineffective and too expensive. Engineers realized that rotating discs handled by a read/write head was the best and most effective system.
The resulting IBM 350 Disc Storage had the dimensions of two refrigerators. 172 centimeters Ă— 152 centimeters Ă— 74 centimeters resulted in a neat device that had to be transported by truck or plane due to its weight of almost a ton.
The hard disk consisted of 50 iron oxide-coated discs stacked on top of each other with a diameter of 24 inches, or 61 centimetres, and stacked 0.72 centimetres apart.
Similar to a jukebox, the disk that was currently being processed was controlled by both arms and processed via the spaces in between. The disks rotated at up to 1200 revolutions per minute. The storage capacity was divided into 50,000 blocks of 100 alphanumeric characters each, with an access time of 600 milliseconds.
(Image:Â IBM )
Hard disk with a storage capacity of 62,500 punched cards
The hard disk could theoretically hold the data from a total of 62,500 IBM punch cards. With a capacity of 80 bytes per card, that would have been exactly 5 megabytes. However, as the parity bit and the space bit had to be subtracted, the 6-bit system effectively had 3.75 megabytes.
The system was introduced on September 14, 1956. In addition to the up to two hard disk cabinets, RAMAC also offered a punch card reader, a printer, and a drum memory of 32 units of 100 alphanumeric characters each, rotating at 6000 revolutions per minute. The system was therefore very, very loud and was usually only operated with hearing protection.
And the system needed a good power supply: The hard disk required a good 2.5 kilowatts. The systems could not be bought, but only rented. And that wasn't cheap: in addition to the RAMAC 305 rental fee of 3200 US dollars per month, there was an additional 650 US dollars for the hard disk.
UNIVAC as a competitor
The RAMAC's biggest competitor was UNIVAC – the world's first commercial computer from competitor Remington-Rand. It had magnetic drums, which had an effective read/write process and made the computer faster than the RAMAC. The disadvantage was the storage space: even with the full configuration of 10 drums, the UNIVAC only offered around a third of the storage space of the first hard disk. This was also the reason magnetic drums disappeared from the market as storage media after a decade.
(Image:Â IBM)
Several further developments appeared until 1959 (Model 2 - 14), until the RAMAC and thus also the production of the first hard disk ended in 1961 after more than 1000 units and was replaced by the IBM 1401, and completely withdrawn from the market in 1969.
The RAMAC was used not only by authorities and the military, but also at the 1960 Olympic Games, where a device was used for data processing. There are also reports that the computer beat a professional chess player during a demonstration at the 1960 Milan trade fair.
Hard disks still calculated too small today
The storage capacity of the system could have been set higher back then. But the marketing department was unsure whether this could be communicated to people, and so they focused on 5,000,000 characters. Thus, the underestimation of storage requirements, which still plagues many hard disk buyers today, was already an attribute of the development of the first hard disk.
With home computers such as PCs, Macs, Amiga and Atari, hard disks, which were initially expensive, gradually found their way into private homes. Wolfgang Back, a veteran presenter of the WDR Computer Club, recalled from the pioneering days of home computers that a colleague once drove from Cologne to Augsburg to buy a 5 megabyte hard disk for an Apple computer at a price of 15,000 Deutschmarks. At the time, he and his colleagues wondered “how he was ever going to fill it up”
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And Amiga users must have thought the same thing at first when the A590 hard disk with an incredible 20 megabytes was released for the Amiga 500 in 1989 (Monkey Island 2 with its eleven floppy disks only appeared three years later). At least there was still a SCSI controller on the plug-in system if it was full faster than expected.
The memory-hungry PC games of the 1990s in particular led to a constant arms race for hard disk storage capacity. Later, MP3s, movies, and photos were added. Nowadays, the good old magnetic disks have been partially retired, at least in the private sector, by fast and robust solid state disks (SSD) and cloud storage – in NAS systems, servers and with several terabytes of data, hard disks with magnetic disks are still the first choice.
(mawi)
